1. Technical Field
The disclosure relates to a data structure of an environment map, an environment map preparing system and method, and an environment map updating system and method.
2. Description of Related Art
A mobile robot that stores map information including information of the position and size of an obstacle such as a piece of furniture in a room, determines a moving route for moving from a current position to a destination while avoiding the piece of furniture using the map information, and moves in the room along the moving route is known (see Japanese Patent Application Publication No. 2003-345438 A (JP 2003-345438 A)).
When the obstacle in the room is a static obstacle of which the position rarely changes such as a bed and the map information includes information of the position and the size of the obstacle, the mobile robot may move while avoiding the obstacle. However, when the obstacle is a static obstacle of which the position changes relatively frequently such as a chair or a trashcan and the static obstacle is located at a certain position at a certain time, the possibility of the static obstacle being at the certain position at another time is low and the possibility of the static obstacle being at a position other than the certain position is high. When the obstacle is a dynamic obstacle such as a person or a pet, the possibility of the position changing is even higher.
The map in JP 2003-345438 A merely includes information on the position and size of an obstacle at the time at which the map information is prepared. Accordingly, in JP 2003-345438 A, the position of an obstacle which changes with the lapse of time, that is, the situation in the room, may not be accurately ascertained. In other words, when the map information merely includes the information on the position and the size of the obstacle, it is difficult to accurately ascertain a situation in a space in which the mobile robot moves.